The present invention relates to an air cleaner which is suited for use in an air-intake system of a small air-cooled internal combustion engine that is adapted to be mounted on a portable power working machine such as a chain saw, a bush cutter, a power blower, etc.
An air cleaner of the type referred to above and known in the prior art is shown in FIG. 4. The air cleaner 60 shown in FIG. 4 is designed to be employed in an air-intake system of a small air-cooled two-cycle gasoline engine to be mounted on a chain saw and is provided with a cleaning filter 61 comprising a bellows-type filter element 62 made from an air-permeable filter paper which is formed into bellows so as to enlarge the filtering area thereof and shaped into a cylindrical body, a reinforcing inner cylinder 66 made from a punched metal sheet having a plurality of through-holes 66a, which is arranged on the inner side of the filter element 62 so as to retain the cylindrical configuration of the filter element 62, and a pair of annular caps 69 having a U-shaped cross-section, which are attached to the top and bottom ends of the filter element 62 and the inner cylinder 66.
The cleaning filter 61 is mounted, through its bottom (the cap 69 which is disposed on the bottom side of the cleaning filter 61), on a mount 82 attached to the upper end of a connecting pipe 80, which is connected with a diaphragm-type carburetor 90. To the mount 82 is attached a cap-fixing bolt 77 in such a manner that the cap-fixing bolt 77 extends upwardly from the bottom of the mount 82 so as to be disposed at the axis of the cleaning filter 61. The cap-fixing bolt 77 receives a screw 74, which is embedded in and fixed to a central boss 72 of a sealing cap 70 having a cup-like shape and which is designed to be rotationally attached to the cap-fixing bolt 77 so as to seal an upper opening within the cap 69 on an upper side of the cleaning filter 61. With the above-described construction, the cleaning filter 61 is clamped between the mount 82 and the sealing cap 70, thereby forming a seal between the interior and the exterior of the cleaning filter 61.
With the air cleaner 60 constructed in the manner described above, since the upper opening of the cleaning filter 61 is closed by the sealing cap 70, the external air is allowed to enter into the air cleaner 60 only through the filter element 62 that forms the outer circumference of the cleaning filter 61. As a result, dust entrained in the external air is removed when the external air passes through the filter element 62, and the cleaned air is introduced into the carburetor 90 through the connecting pipe 80 and then mixed with fuel, the resultant air-fuel mixture being introduced into an intake port of the engine (not shown).
In the operation of a portable power working machine such as a chain saw, a bush cutter, a power blower, etc., dust such as sawdust, powder of cut material and sand-like dust are inevitably generated. When dust of those kinds is allowed to enter together with air into the air intake system of the internal combustion engine, and to collect on the filter member (the filter element 62) of the air cleaner 60, clogging of the filter is caused, thus giving rise to an irregularity of the engine as well as a deterioration in the performance of the engine due to an insufficiency in the flow rate of intake air. Accordingly, it is required in the operation of the portable power working machine to frequently clean the air cleaner 60. However, it is required in the cleaning of the air cleaner 60 of the prior art to dismount or disassemble a machine body cover (not shown), the sealing cap 70, etc., with the use of tools, a task that is quite troublesome for the operator.
The present invention has been made to solve the aforementioned problems. In particular, it is an object of the present invention to provide an air cleaner which makes it possible to easily clean the filter member and is capable of preventing the air cleaner from being clogged with dust.
With a view to attaining the aforementioned object, there is provided, according to the present invention, an air cleaner that includes a cylindrical cleaning filter and a case rotatably receiving the cleaning filter therein. A dust-removing brush is arranged to contact with a filter portion of the cleaning filter, and a device is coupled to the cleaning filter so that the cleaning filter is rotatable from the outside of the case.
In a preferred embodiment of the air cleaner, a manipulating member having a knob is assembled with the cleaning filter, thereby enabling the manipulating member to be rotated together with the cleaning filter, the knob being protruded out of the case.
In another desirable embodiment of the air cleaner, a portion of the case is arranged so that it can be opened or closed so as to make it possible to allow a dust removed from the filter portion by the dust-removing brush and collected in the case to be discharged from the case.
In the aforementioned embodiments of the air cleaner constructed according to the present invention, when the knob that protrudes out of the case is rotated, the cleaning filter is caused to be rotated concurrently with the rotation of the knob. As a result, the dust adhered onto the filter portion is scraped away from the filter portion by the dust-removing brush which is kept in contact with the filter portion. The dust thus removed and collected in the case is then discharged out of the case by opening the aforementioned portion of the case.
The task of cleaning the air cleaner embodying the present invention can be quite easily accomplished by simply rotating the knob. Although it may be impossible to completely remove the dust as in the case when the customary form of cleaning using compressed air, etc. is employed, severe clogging of the cleaning filter that may adversely effect the performance of the engine can be eliminated by cleaning with the dust-removing brush.
Accordingly, it becomes possible, with the air cleaner according to the present invention, to simplify the cleaning task while always assuring some degree of clean level. Therefore, the frequency of the standard cleaning necessitating the removal of the cleaning filter from the case can be remarkably reduced as compared with air cleaners of the prior art, thus obviating the re-adjustment of the carburetor, etc.
For a better understanding of the present invention and of further advantages thereof, reference maybe made to the following description of an exemplary embodiment, taken in conjunction with the accompanying drawings.